Reactive MP-PIC investigation of heat and mass transfer behaviors during the biomass pyrolysis in a fluidized bed reactor

Gas-solid reactive flows during the biomass fast pyrolysis in a three-dimensional bubbling fluidized bed (BFB) reactor are numerically modeled via the multiphase particle-in-cell approach. The model is comprehensively validated with the experimental data regarding the bubble dynamics and product yields. Subsequently, the physical and thermal dynamics of bubbles under the condition of high-temperature biomass pyrolysis in the BFB reactor are explored. The results indicate that the axial segregation induced by size and density difference between sand and biomass results in the occurrence of preferential distribution of biomass particles, which significantly affects the spatial distributions of hydrodynamics, temperature, and species of gas-solid flows. The presence of biomass inlet results in low temperature, large density, and large aspect ratio of rising bubbles around this region. Bubble pressure and bubble temperature increase and decrease along with bed height, respectively. Pyrolysis temperature obviously affects the temperature, pressure, density of bubbles. The results are expected to shed light on the gas-solid hydrodynamics and thermochemical characteristics, especially the dynamics of meso-scale bubble structures in the reactor.

Automated summary

Gas-solid reactive flows during biomass fast pyrolysis in a three-dimensional bubbling fluidized bed reactor were numerically modeled and validated. The study explored the physical and thermal dynamics of bubbles under high-temperature biomass pyrolysis conditions, with a focus on the spatial distributions and characteristics of gas-solid flows.